Welcome to HCM
We understand your concerns
Your boyfriend's doctor might be right. Acid reflux
disease and acidity do create pains around the chest region especially around left chest. Your boy friend might be worried about this and got anxious when the pain comes and goes and anxiety
increases the suffering and he gets red face and flushes.
Don't worry about these. Ask him to consult a doctor and find there is nothing wrong about his body. Then find a psychologist
and get counseling done. I can help you online if you desire so.